How do i export a model in md2 format?
My goal is also to make .MD2 models for my mobile app, so here is my way:


The SceneJS page that MCunha has suggested is a good start.
It says that we need to install the MD2 exporter plugin into Blender. Unfortunately that link for the necessary md2_export_263.py  file is broken, but here is an actual one from jerrylroberts' GitHub repository.
Download it.
I've followed the SceneJS page's instructions on modifying the source code (I don't really know if it's needed or not).
In Blender 2.78c go to File > User Preferences... > Add-ons > Install from File..., browse for the above mentioned (and modified) Python file, then activate it by clicking on its checkbox.
Select the mesh you want to export. It's important for it to be unwrapped and have at least one associated UV-Texture material (according to MCunha's first UFO:IA source). Then go to File > Export > MD2 (.md2)


That's all. I've checked the exported model by G3DViewer in Ubuntu and it seems to be okay.